Lena looks forward to receiving the government-mandated cure that prevents the delirium of love and leads to a safe, predictable, and happy life, until ninety-five days before her eighteenth birthday and her treatment, when she falls in love.

Sixteen-year-old Tessa Gray travels to England in search of her brother only to be abducted by the Dark Sisters, residents of London's Downworld, home to the city's supernatural folk, and she becomes the object of much attention--both good and bad--when it is discovered she has the power to transform at will into another person.